Attempts to make a memory card (semiconductor memory card) housing a nonvolatile semiconductor memory device such as an NAND-type flash memory small in size and high-capacity have been advanced rapidly. Semiconductor devices (semiconductor chips) such as a memory device and a controller device are stacked to be mounted on a wiring board to provide a downsized memory card. Further, there are many cases when memory devices in themselves are stacked in multistage on the wiring board. Electrode pads of the semiconductor device are electrically connected to connection pads of the wiring board via metal wires (bonding wires) by applying wire bonding.
Attempts to make the memory device in itself high-density, high-function, and high-capacity based on the high-density and high-function are advanced in addition to an improvement of a mounting structure of the memory device and the controller device on the wiring board to make the memory card high-capacity. An outer shape of the memory device tends to increase in size to enable the high capacity thereof. Meanwhile, an outer size of the memory device is defined by an SD™ standard and soon. A cut-out portion indicating directions of front-and-rear, obverse-and-reverse of the card when it is attached to a card slot is provided at an outer periphery of the memory card (refer to JP-A 2007-293800(KOKAI)).
When the large-sized memory device is mounted on the wiring board for the memory card, there is a case when the connection between the wiring board and the memory card becomes difficult. This becomes a factor to restrict a size of the memory device which can be mounted on the wiring board. There is a case when the connection between the wiring board and the memory device cannot be secured, if a large memory device is mounted inside an effective area of the wiring board having the cut-out portion provided at a long-edge thereof. If the electrode pads are disposed along the long-edge of the memory device, all of the connection pads cannot be disposed because the cut-out portion of the wiring board becomes an obstacle.
When the memory devices are stacked on the wiring board in multistage, it is studied to stack the plural memory devices in step-wise to perform the wire bonding for the memory devices (refer to JP-A 2005-302871(KOKAI). When the memory devices having the electrode pads arranged along short-edges are stacked in step-wise, a length in a step direction increases as the number of stacked layers increases, and an occupied area of the memory devices relative to the wiring board increases. The size of the memory device is also restricted by the increase of the occupied area of the memory devices. There is a possibility that a memory device having a single short-edge pad structure is not able to correspond to an increase in the number of electrodes resulting from the high-density and high-function.
Further, there is a possibility that a chip size (in particular, a length in the short-edge direction) is not able to satisfy the standard of the memory card such as, for example, a micro SD™ card, in accordance with the high capacity as for the memory device in itself. The memory device generally has a structure in which plural (for example, two pieces of) memory array areas are disposed in parallel, and peripheral circuits are disposed at the same area and in the same direction as a pad column. According to the circuit disposition as stated above, there is a possibility that the standard of the memory card cannot be satisfied because it is difficult to decrease the length in the short-edge direction of the memory device.